Ulva pisiformis Hudson. Corf, pisum, Flor. Dan.;
Harv. in Hook. Brit. Flor. p. 400.; Harv. in Manual,
p. 185.; Meneghini, Monographia Nostochinearum,
p. 1 1 0 .
Hab. In rivulets and fountains, attached to stones, &c.
A p p in : Captain Carmichael. Pools near Barmouth and
Llyn Coron, near Anglesea : Mr. Ralfs. Co. Wicklow
: 5Ir. Moore.
“ Fronds from half a line to two lines in diameter, globular,
firm, smooth, solid, heaped on each other like a parcel of small
shells. Internal filaments rather thinly scattered through the
mass.” — Carm.
“ This species dried and again moistened sometimes emit a
most grateful violet odour, as though it were a species of
Chroolepis, and such as no other Alga of the family of Nostochinea
presents.” — Menegh.
The filaments are moniliform, and exactly correspond with
those of Nostoc foliaceum in size, the young state of which
species, as it agrees with it also in habit, it may eventually
prove to be.
5. N ostoc vesicaeium D. C.
Char. “ Frond globose, plicated, greenish yellow, the internal
viscid mucus escaped, vesicceform, cartilaginous. Filaments
curved, slender, with cells twice as large, thickly interspersed
and terminal:'' — Menegh.
D. C. Flor. F r. vol. iii .; Harv. in Hook. Br. Flor. p. 399.;
Harv. in Manual, p. 184.; Ag. Syst. p. 19.; Meneghini,
Monographia Nostochinearum, p. 108.
Hah. Road-side, near P e r th : G. A. W. Arnott, Fsq.
“ The diameter of the frond varies from a milhmetre to an
inch. The colour in the smaller fronds obscurely green, verges
in the larger to a yellowish brown. Substance firm, cartilaginous,
including a fiuld viscous juice: afterwards, the gelatinous
substance having escaped, empty, vesicseform, membranaceous;
threads moniliform, in the interior substance very lax, in the
external stratum much more curved than in Nostoc commune,
smaller in diameter, they scarcely attain three millimetres ;
but the larger spherical globules, twice as thick, abound, and
sometimes form tracts more or less long, no smaller globule
occurring between. In adult specimens the threads are varicose
wherever they occur.” — Meneghini.
6. N ostoc verrucosum Vauch.
Plate L X X V . Fig. 1.
Char. Frond attached, large, subglobose, in the beginning solid,
externally subcoriaceous, within gelatinous, at length hollow,
vesicceform, verrucose, brownish green; when dried
æruginous. Filaments dense, slender, almost cylindrical.
Nostoc verrucosum Vauch., Hist, des Conf. Tremella flu v iatilis
Dillw., Muse. ; Harv. in Hook. Br. Fl. p. 400. ;
also in Manual, p. 185. ; Meneghini, in loc. cit. ; Thuret,
in Annales des Sciences Naturelles.
Hab. On stones in Alpine streams ; Aberdeen : Dr.
Dichie.
This species may be distinguished from most others of the
genus by the nature of the filaments, which are almost cylindrical.
The species with which it is most likely to be confounded
is Nostocpruiniforme, the filaments of which resemble
It closely, but are considerably larger ; in other respects the
two species are widely different, being estranged in form,
habit and consistence.
7. N ostoc pruiniforme Ag.
Plate L X X V I . Figs. 3, 4.
Char. Frond unattached, solitary, globose, smooth, olivaceous,
gelatino-coriaceous, within watery. Filaments somewhat
thick, almost cylindrical.
Ag. Disp. p. 4 5 .; Berk. Gl. p. 48. t. 19. f. 2. ; Lyngb.
u 2